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  <title>Get and/or set the current cache limiter</title>

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</div><hr /><div id="function.session-cache-limiter" class="refentry">
 <div class="refnamediv">
  <h1 class="refname">session_cache_limiter</h1>
  <p class="verinfo">(PHP 4 &gt;= 4.0.3, PHP 5)</p><p class="refpurpose"><span class="refname">session_cache_limiter</span> &mdash; <span class="dc-title">Get and/or set the current cache limiter</span></p>

 </div>

 <div class="refsect1 description" id="refsect1-function.session-cache-limiter-description">
  <h3 class="title">说明</h3>
  <div class="methodsynopsis dc-description">
   <span class="type">string</span> <span class="methodname"><strong>session_cache_limiter</strong></span>
    ([ <span class="methodparam"><span class="type">string</span> <code class="parameter">$cache_limiter</code></span>
  ] )</div>

  <p class="para rdfs-comment">
   <span class="function"><strong>session_cache_limiter()</strong></span> returns the name of the
   current cache limiter.
  </p>
  <p class="para">
   The cache limiter defines which cache control HTTP headers are sent to
   the client.  These headers determine the rules by which the page content
   may be cached by the client and intermediate proxies.  Setting the cache
   limiter to <em>nocache</em> disallows any client/proxy caching.
   A value of <em>public</em> permits caching by proxies and the
   client, whereas <em>private</em> disallows caching by proxies
   and permits the client to cache the contents.
  </p>
  <p class="para">
   In <em>private</em> mode, the Expire header sent to the client
   may cause confusion for some browsers, including <span class="productname">Mozilla</span>.
   You can avoid this problem by using <em>private_no_expire</em> mode. The
   <em>Expire</em> header is never sent to the client in this mode.
  </p>
  <p class="para">
   Setting the cache limiter to <em>&#039;&#039;</em> will turn off automatic sending
   of cache headers entirely.
  </p>
  <p class="para">
   The cache limiter is reset to the default value stored in
   <a href="session.configuration.html#ini.session.cache-limiter" class="link">session.cache_limiter</a>
   at request startup time. Thus, you need to call
   <span class="function"><strong>session_cache_limiter()</strong></span> for every
   request (and before <span class="function"><a href="function.session-start.html" class="function">session_start()</a></span> is called).
  </p>
 </div>


 <div class="refsect1 parameters" id="refsect1-function.session-cache-limiter-parameters">
  <h3 class="title">参数</h3>
  <p class="para">
   <dl>

    
     <dt>
<em><code class="parameter">cache_limiter</code></em></dt>

     <dd>

      <p class="para">
       If <em><code class="parameter">cache_limiter</code></em> is specified, the name of the
       current cache limiter is changed to the new value.
      </p>
      <table class="doctable table">
       <caption><strong>Possible values</strong></caption>
       
        <thead>
         <tr>
          <th>Value</th>
          <th>Headers sent</th>
         </tr>

        </thead>

        <tbody class="tbody">
         <tr>
          <td><em>public</em></td>
          <td>
           <div class="example-contents">
<div class="headercode"><pre class="headercode">Expires: (sometime in the future, according session.cache_expire)
Cache-Control: public, max-age=(sometime in the future, according to session.cache_expire)
Last-Modified: (the timestamp of when the session was last saved)</pre>
</div>
           </div>

          </td>
         </tr>

         <tr>
          <td><em>private_no_expire</em></td>
          <td>
           <div class="example-contents">
<div class="headercode"><pre class="headercode">Cache-Control: private, max-age=(session.cache_expire in the future), pre-check=(session.cache_expire in the future)
Last-Modified: (the timestamp of when the session was last saved)</pre>
</div>
           </div>

          </td>
         </tr>

         <tr>
          <td><em>private</em></td>
          <td>
           <div class="example-contents">
<div class="headercode"><pre class="headercode">Expires: Thu, 19 Nov 1981 08:52:00 GMT
Cache-Control: private, max-age=(session.cache_expire in the future), pre-check=(session.cache_expire in the future)
Last-Modified: (the timestamp of when the session was last saved)</pre>
</div>
           </div>

          </td>
         </tr>

         <tr>
          <td><em>nocache</em></td>
          <td>
           <div class="example-contents">
<div class="headercode"><pre class="headercode">Expires: Thu, 19 Nov 1981 08:52:00 GMT
Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0
Pragma: no-cache</pre>
</div>
           </div>

          </td>
         </tr>

        </tbody>
       
      </table>

     </dd>

    
   </dl>

  </p>
 </div>


 <div class="refsect1 returnvalues" id="refsect1-function.session-cache-limiter-returnvalues">
  <h3 class="title">返回值</h3>
  <p class="para">
   Returns the name of the current cache limiter.
  </p>
 </div>


 <div class="refsect1 changelog" id="refsect1-function.session-cache-limiter-changelog">
  <h3 class="title">更新日志</h3>
  <p class="para">
   <table class="doctable informaltable">
    
     <thead>
      <tr>
       <th>版本</th>
       <th>说明</th>
      </tr>

     </thead>

     <tbody class="tbody">
      <tr>
       <td>4.2.0</td>
       <td>
        The <em>private_no_expire</em> cache limiter was added.
       </td>
      </tr>

     </tbody>
    
   </table>

  </p>
 </div>


 <div class="refsect1 examples" id="refsect1-function.session-cache-limiter-examples">
  <h3 class="title">范例</h3>
  <p class="para">
   <div class="example" id="example-4668">
    <p><strong>Example #1 <span class="function"><strong>session_cache_limiter()</strong></span> example</strong></p>
    <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /><br /></span><span style="color: #FF8000">/*&nbsp;set&nbsp;the&nbsp;cache&nbsp;limiter&nbsp;to&nbsp;'private'&nbsp;*/<br /><br /></span><span style="color: #0000BB">session_cache_limiter</span><span style="color: #007700">(</span><span style="color: #DD0000">'private'</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$cache_limiter&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">session_cache_limiter</span><span style="color: #007700">();<br /><br />echo&nbsp;</span><span style="color: #DD0000">"The&nbsp;cache&nbsp;limiter&nbsp;is&nbsp;now&nbsp;set&nbsp;to&nbsp;</span><span style="color: #0000BB">$cache_limiter</span><span style="color: #DD0000">&lt;br&nbsp;/&gt;"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
    </div>

   </div>
  </p>
 </div>


 <div class="refsect1 seealso" id="refsect1-function.session-cache-limiter-seealso">
  <h3 class="title">参见</h3>
  <p class="para">
   <ul class="simplelist">
    <li class="member"><a href="session.configuration.html#ini.session.cache-limiter" class="link">session.cache_limiter</a></li>
   </ul>
  </p>
 </div>


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